Cost estimation for building an architect-designed house - Munich surrounding area

We have a pair of parents who will regularly come from the USA to Europe and occasionally want to stay with us. The other pair of parents is in poor health and we also want to take precautions here. Looking further into the future, the granny flat offers the possibility to accommodate an au pair or to provide a child with their first opportunity to move out.

It sounded like you were getting at something specific.

OK, these are understandable reasons for a granny flat. Often you read that the granny flat is supposed to be rented out and the rent should contribute to refinancing. But this calculation never works out, and you also get strangers in the house, which negates the advantage of a single-family home.

When health is impaired, always keep in mind that aids such as walkers, ... require more movement space. This must then be taken into account when planning a granny flat, which increases its size in terms of area.

If I compare your information with our planning, I consider 1.5 - 1.7 million including architect, engineer, etc. without fixtures and extras like a pool to be realistic. We are building in the Rhein-Main area (slightly cheaper than M), but on a hillside location, which might compensate for that.

Why a general contractor when you are already working with an architect? In my opinion, you have more control over the costs without a general contractor... and with the expenses, I would really want to have everything under control. Read the posts from or search for Baulotse Hoffmann on the internet.

Besides - is it even worth looking at prefabricated house providers for our project (also financially), or does the recommendation rather lean towards an individual solid-architect’s house?

What do you expect from a prefabricated house provider?

Although I have already dealt very intensively with prefabricated houses, I have never had a conversation with a provider. I assume it definitely makes sense to obtain at least 1-2 comparison offers here.

Spontaneously, I initially hesitated whether you would have (mis)answered the question "what do you expect from a prefabricated house provider" as the question "what do you expect from a prefabricated house provider." In the meantime, I am unsure what role a prefabricated house provider even plays for you here:
A. that of a builder (in terms of the question "stone or wood – which approach is more suitable for this building wish");
B. that of a donor of a price expectation (in the sense of the thesis that the provider of an industrially manufactured house understands best how to precisely calculate the manufacturing effort);
C. that of a donor of a comparison standard* (in terms of authenticating other offers and weighting providers as equally or more or less profit-oriented)?

In general, a house X with equipment X always costs (apart from inaccuracies) the same price, and to recognize or deny the equivalence of different construction methods is, in a way, a "religious" question. Objectively, a (cost) advantage applies to the "prefabricated" house (in the sense of wood frame panel construction) in the key stages "KfW40", "Passive house," or similar, because with its wall construction as a thermal insulation integral system it meets the requirements more easily and with longer experience of the manufacturers. It also has small advantages in static quirks like corner windows and the like, which can also be realized somewhat more cheaply. Otherwise, it is six of one, half a dozen of the other.

*) non-thinking comparisons are actually only possible on the basis of an identical specification of services, which in turn is only partially transferable between stone and wood construction methods

Although the amounts are by now normal for the area, I would still feel uneasy walking into a prefab house provider with such a budget. Maybe I'm wrong, but the constraints they impose on you would, in my opinion, backfire on you. In this price category, you don’t want to choose from 3 door handles, but from 100, preferably with style recommendations from the interior designer.

Why use a general contractor (GU) if you’re building with an architect anyway? In my opinion, you have more influence on the costs without a GU... and with the expenses involved, I would really want to have everything under control. Read the posts by @11ant or search for Baulotse Hoffmann on the internet.

/ and P.S. to:

Also – is it even financially worthwhile to consider prefab house providers for our project, or is the recommendation more in the direction of an individual solid construction architect-designed house?

Possibly D. was (also) about who gets to blow a big budget more representatively? ;-)

Generally, I see architectural planning as advisable for a house of this size, since the total living area catalogs are certainly quite limited, i.e., there are few well-tested house models found there. Also, the order volume strongly calls for a proper tender; the “method” of sending floor plans and expecting prices written on them back would be, to put it mildly, too imprecise here.

I would initially start planning with the architect and, in the pause between Module A and Module B (i.e., after performance phase 2, explained at the mentioned point in "A House Construction Schedule, Also for You: the HOAI Phase Model!"), reflect on whether one wants to realize the later design in masonry or timber construction; if there is no preference regarding this, one can use the preliminary designs to initiate first talks with GUs of both construction methods.

The decision whether to award to a GU can quite well be left to the result of the tender (where a smart architect never rules out that bidders apply for all lots – I do not recommend restricting the tender only to GUs as participants). If the client insists on believing in the magic of awarding to a GU anyway, however, this has consequences for the further planning process: because then one should not start the entire Module B but only performance phase 3, otherwise performance phase 4 would be done twice.

Although the amounts are now normal for the area, I would still have a bad feeling about marching up to a prefab house provider with such a budget. Maybe I am wrong, but the corset that they impose on you would, in my opinion, trip you up. In this price category, you don’t want to choose from 3 door handles, but from 100 and preferably with style advice from the interior designer.

I completely agree with you! We are talking about a budget dimension where maximum individuality should actually be possible.

At first, I hesitated whether you would have answered the question "what do you expect from a prefab house provider" as the question "what do you expect from a prefab house provider" (mis?) answered. Meanwhile, I am unsure about what role a prefab house provider actually plays for you here: A. that of a builder (in the sense of the question "stone or wood – which path is more suitable for this building desire"); B. that of a giver of a price idea (in the sense of the thesis that the provider of an industrially manufactured house understands best to precisely calculate the manufacturing effort); C. that of a provider of a comparison standard* (in the sense of authenticating other offers and weighting the providers as equally or more or less profit-hungry)?

In general, a house X with equipment X always costs (apart from inaccuracies) the same price, and to acknowledge or deny the equivalence of different construction methods is, in a way, a "religious" question. Objectively, the (cost) advantage lies with the "prefab" house (in the sense of timber frame panel construction) in the fat stages "KfW40," "passive house," or similar, because with its wall construction as a thermal insulation integral system it meets the requirements more easily and with longer experience of the manufacturers. It also has small advantages with structural small things like corner windows and the like, which are also somewhat cheaper to realize. Otherwise, it’s six of one, half a dozen of the other.

*) non-thinking comparisons are actually only possible on the basis of an identical scope of services, which is only partially transferable between stone and timber construction methods

Good question – what was I wanting to get at anyway?

Basically, we have a total budget of 3 million euros. Of that, 1.5 million euros are gone for the land. I would rather not strain ourselves financially any further, and the absolute top pain threshold would be 1.7 million euros for the house – including a granny flat, furnishings, garden work, possibly a pool, and everything else.

Now I face the huge challenge of figuring out which approach will get me closest to our dream house while not exceeding the budget. Cost drivers like the granny flat and KNX are set. A pool would be nice but is optional.

Even if you cannot achieve 100% comparability between the architect-designed house and a prefab house, I would like to answer the question for myself: Can the prefab house provider, with the same written requirements, offer me more house (including extras) than the variant with solid construction + architect?